const immutableReducer = (state = ["Do not mutate state!"], action) => {
    switch (action.type) {
        case "ADD_TO_DO":
            return [...state, action.todo];
        default:
            return state;
    }
};

const addToDo = todo => {
    return {
        type: "ADD_TO_DO",
        todo
    };
};

const store = Redux.createStore(immutableReducer);
